The diagram to the right illustrates the inter-actions ofthe amino acid side chains of two a-helicalpolypeptide strands in a coiled-coil, viewed end-on andprojected along the helix axes from the N-terminal tothe C-terminal end. Are the macrodipoles of the two a-helices oriented parallel or anti-parallel? For this projec-tion is the positive end of the macro-dipole in the sur-face of the paper or below the surface?fCbgeda'a d'gb'f'

Coiled coils are super secondary structures formed as 2 or more alpha helices twist around each…

Answered: The diagram to the right illustrates…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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Similar questions

A helical wheel is a two-dimensional representation of a helix, a view along its central axis Use the helical wheel diagram shown here to determine the distribution of amino acid residues in a helical segment with the sequence –Val–Asp–Arg–Val–Phe–Ser–Asn–Val–Cys–Thr–His–Leu–Lys–Thr–Leu–Gln–Asp–Lys–What can you say about the surface properties of this helix? How would you expect the helix to be oriented in the tertiary structure of an integral membrane protein?
Alpha-helices have 3.6 amino acid residues per turn, ie a helix 36 amino acids long would form 10 turns, and The axial distance between adjacent residues is 3.5 Angstroms. Beta-helices have two residues per repeat unit which gives the beta-strand a 7 Angstrom pitch. This compares with the alpha-helix where the axial distance between adjacent residues is only 1.5 Angstroms. Then how many residues in an alpha-helix conformation would it take to traverse the same distance as 10 residues in beta-strand conformation?
The domain of a protien is approximately 350 residues in length. what is length (in A°) of this domain? if this same peptide segment were a true alpha helix, how long would it be? if the same segment were beta sheet, what would its length be?
The following are sequences from three different alpha helices found inhuman proteins: hBak(72-87): GQVGRQLAIIGDDINR hCB1(196-210): VTASFTASVGSLFLT hCB2(248-262): LVLAVLLICWFPVL Classify each of these three helices as either a) mostly hydrophobic, b)mostly hydrophilic, or c) amphipathic. Use the helical wheel to explainyour answers. Given the character of these helices, in which part of the protein wouldyou expect them to reside?
A synthetic polypeptid made up of L-glutamic acid residues is in a random coil configuration at pH 7.0 but changes to alpha helical when the pH is lowered to 2.0. Explain this pH-dependent conformational transition.
α‑Keratin is an intermediate filament with a basic structural unit of two α helices in a coiled coil. Each helix has a seven‑residue repeating unit (heptad repeat). A representation of the α helices of a coiled coil dimer is shown. Each letter represents a different amino acid residue.
Consider the following peptide to answer the questions below: A M A K K E S H I F T A I D E What is the total charge of this peptide at pH = 5? What is the N terminal amino acid (full name)? C terminal amino acid? How many fragments would result if this peptide underwent proteolytic cleavage with V-8 protease and what are these fragments (list them)? Would this peptide be a candidate to form an alpha helix? Why or why not
The unfolding of the α helix of a polypeptide to a randomly coiled conformation is accompanied by a large decrease in a property called specific rotation, a measure of a solution’s capacity to rotate circularly polarized light. Polyglutamate, a polypeptide made up of only L-Gluresidues, has the α-helix conformation at pH 3. When the pH is raised to 7, there is a large decrease in the specific rotation of the solution. Similarly, polylysine (L-Lys residues) is an α helix at pH 10, but when the pH is lowered to 7 the specific rotation also decreases, as shown by the following graph. What is the explanation for the effect of the pH changes on the conformations of poly(Glu) and poly(Lys)? Why does the transition occur over such a narrow range of pH?
Estimate the length, in nm, of the four identical beta-strands drawn in blue in panel (B) of the image below, if they consists of only the amino residues of the two alpha-helices highlighted in purple in panel (A) of the image below. Assume that the amino acid residues of the two alpha-helices combined were folded in four beta-strands of identical length.
Here’s a Ramachandran plot. Give the dihedral angles--phi and psi--that are characteristic of a left handed helix.
Proline is known as a beta sheet and alpha helix "breaker ," therefore proline is rarely found in beta sheets or alpha helices. why do you think this is? In your explanation, you should describe the specific molecular interactions necessary for the formation of alpha-helices and beta-sheets. Please be as specific as possible.
The structure of an alpha helix orients the oxygens of the carbonyl group of the peptide bond towards the C-terminal end of the helix while the hydrogens of the NH groups orient toward the N-terminal end, thus imparting a dipole along the length of the helix. As a result, which kinds of amino acids would favor the C-terminal end, and which would favor the N-terminal end? negatively charged, positively charged positively charged, negatively charged negatively charged, hydrophobic positively charged, hydrophobic hydrophobic, negatively charged hydrophobic, positively charged

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